Description
    Several species of Fusarium are known to cause cankers in black walnut in the Midwest and North Carolina. Trees in other States are also probably affected by the canker.

    Elongate cankers of various lengths usually occur on the lower portions of the main stems of young trees, near the ground line. However, cankers may also occur higher on the stem or on branches in the lower crown of young trees. Cankers first appear as breaks in the bark or as expanding sunken areas. Darkly stained, diseased wood can be found beneath the bark. An affected tree often produces sprouts near the canker or at the base of the stem. Sometimes tiny pinholes caused by an ambrosia beetle can be found within the cankered area.

Injury
    Affected trees show cankered, stained areas on the stems. An otherwise normal-looking tree that is producing many basal sprouts is commonly cankered. The primary injuries caused are wilting of leaves and dieback of the top. When the top has died, a sprout may take over and replace the lost tree, but several years of growth are lost.

Control
    Cut and remove diseased trees from the plantation. Prune dormant trees and burn or remove pruning debris from the area.